PACIFIC, Mo. — After days spent sandbagging, rounding up livestock and spiriting their valuables to higher ground, residents along the Meramec River basin watched Saturday as the volatile river neared record levels. The river engulfed hundreds of homes, threatened to overwhelm a major Interstate and left residents to worry what they would come home to when the water finally receded.

By early Saturday, the Meramec River, which snakes through the hill country before feeding into the Mississippi, had crested here, about 30 miles west of St. Louis, and in nearby Eureka. In the afternoon, the National Weather Service reported that the river had peaked in Valley Park at 37.83 feet, less than two feet shy of the record, about 20 miles west of St. Louis.

In Pacific, the Meramec crested at 28.84 feet, below earlier estimates and well shy of the record flood of 1982 when the river topped out at 33.6 feet. Nonetheless, the river spread wide across the town, inundating more than 30 city blocks and displacing more than 500 people.

As the water lapped at sandbags and flowed through living rooms, many people were left staring helplessly at their homes a few hundred yards away.

“My first thought was to keep the kids safe,” she said. “All my flowers were starting to come up, but now I’m wondering: Am I going to have a place to take my daughters? Are we going to have a place to live? It’s scary.”

Not everyone in the flooded area left. Jim Nantz, whose home is built on an elevated foundation roughly a half-mile from the river, spent much of Friday barbecuing on his front porch.

“My place has got about three feet of water around it and in the crawl space, but there’s no water in the house,” Mr. Nantz said.

The storm, which caused flooding in counties from Texas to Pennsylvania, has been blamed for at least 16 deaths. After showering more than a foot of rain on parts of Missouri and Arkansas earlier in the week, the storm moved northeast, where the National Weather Service said it dumped more than a foot of snow on parts of the Upper Midwest.

But the worst flooding has been in Missouri, where President Bush approved federal disaster aid this week for St. Louis and 70 Missouri counties. The flooding has been most concentrated along the Meramec River and in the southeastern part of the state, where at least 200 homes were evacuated in Cape Girardeau County, said Susie Stonner of the State Emergency Management Agency.

On Saturday, traffic was stalled along Interstate 44 west of St. Louis, where crews barricaded against the river’s swelling waters. Near Valley Park, waters drenched the Interstate’s shoulders, submerging the interchange with Highway 141.

“We let the citizens be their own guide,” Mr. Whitteaker said. “The major concern was that this was the first initial test of the levee. I don’t blame anyone for leaving.”

But John Beard, who lives within 400 feet of the levee, had refused to decamp.

“Why would we spend $50 million on a levee if we’re going to get scared and move every time the water comes up?” Mr. Beard said, standing in his yard. “It defeats the purpose.”

By Saturday afternoon the waters in Pacific had begun to recede and residents were allowed to enter the flooded area. Mayor Herbert Adams said he would allow residents to enter for a “quick inspection” of their homes. He added that in light of earlier flood estimates, he was hopeful the damage would not be too severe.

In Pacific, Jim Smith, a real estate agent who had left his offices, said people would keep coming back no matter how many times it flooded.

“We’ve been here for 200 years,” Mr. Smith said. “It’s hard to leave. We love these river bottoms.”

Among those who will be returning is Gerald Grimm, a semiretired cattle farmer whose property has been flooded three times since 1982.

“It’s going to eat into my pocketbook,” said Mr. Grimm, 79. “But I’ve been there all my life, I figure I’ll finish it there.”

A version of this article appears in print on , on Page A12 of the New York edition with the headline: Worried Residents Watch as River Crests in Missouri. Order Reprints|Today's Paper|Subscribe